The radial nerve runs down the underside of your arm and controls movement of the triceps muscle, which is located at the back of the upper arm. The radial nerve is responsible for extending the wrist and fingers. It also controls sensation in part of the hand.
Injury to the radial nerve may result in radial neuropathy, also called radial nerve palsy. Radial nerve injury may be due to physical trauma, infection, or even exposure to toxins. It often causes numbness and tingling or burning pain. It can also be painless. The condition may cause weakness or difficulty moving your wrist, hand, or fingers.
In many cases, this condition will improve if the underlying cause is treated.
Injury to the radial nerve has a variety of possible causes. These include:
- fracturing your humerus, a bone in the upper arm
- sleeping with your upper arm in an awkward position
- pressure from leaning your arm over the back of a chair
- using crutches improperly
- falling on or receiving a blow to your arm
- long-term constriction of your wrist
The most common causes of radial nerve injury are breaking your arm, overusing your arm, and sports and work accidents. Depending on the level of injury, you may experience a complete laceration of the radial nerve. This occurs when the nerve is severed. It can cause symptoms that are similar to more minor injuries. A nerve laceration usually requires surgical repair.
Certain actions, when repeated often enough, can lead to radial nerve damage. Movements that involve both grasping and swinging movements, such as swinging a hammer, can lead to nerve damage over time. As the radial nerve moves back and forth over the bones of your wrist and forearm, there’s potential for the nerve to become trapped, pinched, or strained from these activities.
Lead poisoning can also lead to long-term nerve damage. Over time, the lead toxin can cause damage to the nervous system as a whole.
Certain health conditions that affect your whole body may damage one nerve. Kidney disease and diabetes may cause inflammation, fluid retention, and other symptoms that can, in turn, lead to nerve compression. This could affect the radial nerve or other nerves in your body.
A radial nerve injury usually causes symptoms in the back of your hand, near your thumb, and in your index and middle fingers.
Symptoms may include a sharp or burning pain, as well as unusual sensations in your thumb and fingers. It’s common to experience numbness, tingling, and trouble straightening your arm. You may also find that you can’t extend or straighten your wrist and fingers. This is called “wrist drop” or “finger drop,” and it doesn’t occur in all cases.
If you think you’ve injured your radial nerve, your doctor will start by asking you about your symptoms and when they began. This may help pinpoint what caused the injury.
Your doctor will also do a physical exam. They will look at your affected arm, hand, and wrist, and compare it to your healthy arm, hand, and wrist. They may ask you to extend and rotate your arm to see if the injury affects your range of motion. Your doctor will also ask you to extend your wrist and fingers, checking for any weakness or loss of muscle tone.
Your doctor may order tests to rule out other causes of your symptoms. For example, you may have blood tests to check your blood sugar and vitamin levels, as well as your kidney and thyroid function. These tests check for signs of other conditions associated with nerve damage, such as diabetes, vitamin deficiencies, or diseases of the kidney and liver. A CT scan or MRI can also look for diseases within your head, neck, or shoulders that may result in pressure on your radial nerve.
Your doctor may also consider electromyography (EMG) and nerve conduction tests. An EMG measures the electrical activity in your muscle. A nerve conduction test measures the speed at which impulses travel along your nerves. These tests can help determine if you are experiencing a problem in your nerve or in your muscle. They may also show whether the radial nerve is damaged.
In very rare cases, your doctor may request a nerve biopsy. This involves taking a small sample of the nerve and examining it to determine what is causing the damage.
The goal of treatment for radial nerve injury is to relieve symptoms while maintaining movement of your wrist and hand. The best treatment depends on the underlying cause. In some cases, symptoms go away slowly on their own without intervention. Your doctor may prescribe medication or other therapies to help manage your symptoms.
There are several different first-line treatment options available. These include:
- analgesic or anti-inflammatory medications
- antiseizure medications or tricyclic antidepressants (prescribed to treat pain)
- steroid injections
- anesthetic creams or patches
- braces or splints
- physical therapy to help build and maintain muscle strength
Some people choose transcutaneous electrical nerve stimulation (TENS) to treat nerve damage. This therapy involves placing several adhesive electrodes on the skin near the affected area. The electrodes deliver a gentle electric current at varying speeds.
Physical therapy to build and maintain muscle strength can help to heal and improve nerve function. Massage treatment is another option. Massage can break up scar tissue and make the radial nerve more responsive.
Analgesic or anti-inflammatory medication can help relieve the pain of a radial nerve injury. It may also help the injury heal faster. A single cortisone shot in the affected area can relieve pain. Anesthetic creams or patches can also be used to relieve pain, while still allowing movement.
It’s also common to use a brace or splint to immobilize the nerve. This might not sound like the most convenient option, but it may prevent you from reinjuring the nerve while it’s healing.
Less traditional treatment methods, such as acupuncture and chiropractic adjustments, are also an option. Keep in mind that evidence about whether some of these treatments work is mixed.
Most people with a radial nerve injury will recover within three months of starting treatment if the nerve is not torn or lacerated. But some cases ultimately require surgery. If your radial nerve is entrapped, surgery can relieve pressure on the nerve. If there is a mass, such as a benign tumor, on your radial nerve, you may need surgery to remove it.
The goal of surgery is to repair any damage to the nerve. Occasionally, when it is thought that the nerve will not heal, tendon transfers can be performed to restore function to the extremity. After surgery, you will need to wear a brace or splint to allow the injury or tendon transfer to heal. Your doctor will refer you to a physical therapist for rehabilitation to restore range of motion and strength.
You can prevent most radial nerve injuries if you avoid putting prolonged pressure on your upper arm. Avoid behaviors that can lead to nerve damage, such as repetitive motions or remaining in cramped positions while sitting or sleeping. If you work in an occupation that requires repetitive motions, take steps to protect yourself by taking breaks and switching between tasks that require different movements.
The long-term prognosis for a radial nerve injury varies greatly depending on the cause and severity of the injury. In most cases, a full recovery is possible. First-line treatment methods will generally heal most radial nerve injuries within 12 weeks.
If your nerve damage is the result of an underlying medical condition, such as diabetes or alcoholism, talk to your doctor about how to manage your symptoms.
People who are younger when the injury occurs and people who have additional nerve damage injuries tend to recover the most quickly. If surgery is needed, a full recovery can take from six to eight months.